1. Field of the Invention
This invention relates to the formation of certain linear diacetates from their respective C.sub.4 olefins. More particularly, this invention relates to the oxidation of certain defined C.sub.4 olefins under conditions which favor the formation of the corresponding linear 1,4-diacetates over the branched diacetates, and converting the said linear 1,4-diacetates to butanediol, employing a novel olefin-activated palladium metal catalyst.
In a like manner, isobutylene may be converted to the corresponding branched alcohol and isomeric butanediols.
2. Description of the Prior Art
P. M. Henry (J. Org. Chem. 32, 2575 (1967), describes the oxidation of butene-1 and cis-and trans-butene-2 to their respective chloroacetates and diacetates, using a catalyst system comprised of palladium acetate, cupric chloride, and lithium acetate at temperatures of about 100.degree. C. and at maximum olefin pressure. The yield of diacetates, however, is below 20 percent, and of linear 1,4-diacetates is below 0.4 percent.
Shimizu, U.S. Pat. No. 3,872,163, describes the oxidation of various C.sub.4 's, particularly butadiene, to form butene diacetates employing conventional palladium catalysts, preferably in the presence of certain metal acetates. The use of applicant's unique olefin-activated palladium, described herein below is not taught or suggested herein. Hinnenkamp, U.S. Pat. No. 4,435,598; Scharfe, U.S. Pat. No. 3,970,713; and Onoda 4,016,200 also teach conventional methods for oxidizing olefins in the presence of palladium catalysts, wherein said catalysts are prepared by reducing palladium salts with various reducing agents including olefins under routine reduction conditions. Scharfe, whose catalyst is impregnated with potassium acetate for use in oxidizing propylene to allyl acetate, additionally makes the obvious point that it is commercially advantageous, although not essential, to carry out the reduction before introducing the volumes of oxygen needed for oxidation. Nowhere, however, is there any recognition of preparing the catalyst in the substantial absence of oxygen, or the benefits to be derived therefrom. Similarly, Hartley, "The Chemistry of Platinum and Palladium," Wiley and Sons, pp. 386-390 and 412-417 (1973) discloses a method for making a palladium chloride catalyst complexed with ethylene for use in olefin acetylation to form vinyl acetate. As with Shimizu, however, none of these prior art techniques disclose the use of a unique olefin-activated palladium metal catalyst as defined herein to oxidize butene to form butene diacetates.
It is thus an object of this invention to provide an alternate method for the oxidation of certain butenes to their corresponding linear 1,4-diacetates in increased ratios over the branched diacetates employing a unique olefin-activated palladium catalyst, which diacetates may be converted to butanediol.
These and other objects of the invention will be described in further detail below.